The invention concerns magnetic separators used to remove ferromagnetic particles from a liquid, as used in conjunction with removal of contaminants machining fluids so as to allow its reuse. In the large scale production of machined metal parts, such as automotive engine components machining, fluid used to cool and lubricate the cutting tools is collected and purified and recirculated for reuse, filters are used to purify the fluid.
It is sometimes desirable to separately remove the metal particles, as for example the fines produced when grinding a part, as to avoid clogging of the filter media.
Magnetic separators have heretofore been developed for this purpose and have been commercially available for a number of years.
These prior separators include a closely spaced train of elongate magnetic bars comprised of nonmagnetic tubes filled with short magnetic cylinders, and the fluid is caused to flow between the spaces between the bars, the steel or iron particles attracted to the surfaces of the bars and held thereto to be removed from suspension in the liquid. The train of bars supported on chain loops is driven to bring each pair of bars in to a scraping station where the accumulated particles are scraped off and deposited in a discharge chute.
Such a device is shown in U.S. Pat. Nos. 4,031,011; 4,261,826; and 4,209,403.
In the device of the type shown in these patents, the bars are mounted to chain arranged in a closed loop partially disposed in a tank, which loop is advanced to bring each bar into the scraping station. The fluid is introduced into the tank space outside the loop of magnetic bars and flows into the space within the loop by flowing through the spaces between the bars. The spacing and flow rates are set to produce a sufficiently low flow velocity so that the particles can migrate to the bars.
Since the flow is from outside the loop into the space within the loop, some of the metal particles are able settle to the tank bottom before entering the spaces between the bars, such particles accumulating in the tank to require clean out of the tank at frequent intervals.
Distributor plates are provided to insure relatively even flows through all of the pairs of adjacent bars, but these are of necessity located within the loop, requiring disassembly of the chain loops to remove the plates for cleaning.
These devices also have a complex mechanism for driving the loop and the scraper mechanism, and the scraper mechanism itself is subject to misalignments.
In copending allowed patent application Ser. No. 09/502,145, filed Feb. 11, 2000, now U.S. Pat. No. 6,277,276, issued Aug. 21, 2001 here incorporated by reference, an improved scraper mechanism is described and claimed for the bars of a magnetic separator.
It is the object of the present invention to provide an improved magnetic separator of the type described in which all metal particles must pass by the magnetic bars so as to avoid settling out of these particles to the tank bottom.
The above object and others which will become apparent upon a reading of the following specification and claims are achieved by directing the inlet flow into a closed space within the loop of bar magnets and inducing flow radially outwardly through the spaces between the bars. This insures that all particles must pass through bar spaces and cannot settle out to the tank bottom prior to being subjected to the strong magnetic field between the bars.
The distributor plates are located outside the bar loop so as to be easily removable for cleaning.